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Is Plant Liberation on the Menu?

By Michael Marder May 8, 2012 9:00 pmMay 8, 2012 9:00 pm

The Stone is a forum for contemporary philosophers and other thinkers on issues both timely and timeless.

I would like to thank the many readers who took the time to respond to my previous post for The Stone, “If Peas Can Talk, Should We Eat Them?” Among the approximately 350 comments were several who opposed or misread the argument underlying the piece: that plants have a more complex existence than most people believe, and that that fact should move us to reconsider our ethical approach to eating them. I’d like to address some of those misreadings and objections.

It seems that Aristotle was on the right track when he argued for the existence of a vegetal soul.

Although recent studies in botany are certainly groundbreaking, both Western and non-Western philosophers have been aware of what we may now call “plant subjectivity” for millennia. Most famously, Aristotle postulated the existence of a vegetal soul with its capacities for reproduction growth, and nourishment, as the most basic stratum of life. To Aristotle, all living beings, including animals and humans, are alive by virtue of sharing this rudimentary vitality with plants. Other levels of the psyche — the sensory and the rational — then presuppose the presence of vegetal soul for their proper functioning and actualization.
Contemporary research into plant intelligence, spearheaded by Anthony Trewavas (University of Edinburgh), Stefano Mancuso (University of Florence) and Richard Karban (University of California, Davis), among others, complicates this tripartite division. For example, studies have found evidence of “deliberate behavior” in plants: foraging (note that the botanists themselves use this word usually associated with animal behavior) for nutrients, the roots can drastically change their branching pattern when they detect a resource-rich patch of soil, or they can grow so as to avoid contact with roots of other members of the same species, in order to prevent detrimental competition. Of course, plants are not capable of deliberation or of making decisions in the human sense of the term. But they do engage with their environments and with one another in ways that are incredibly sophisticated, plastic and responsive — in a word, intelligent, though not perhaps conscious.

This is why it is a blatant mistake to equate plants with machines. The mistake itself has a long history, parallel to the Cartesian treatment of animal and human bodies as automatons. We cannot rid ourselves of such preconceptions overnight: the plant-as-machine metaphor has become so entrenched that it is difficult to digest evidence to the contrary. In the age of communication technologies, it is tempting to compare plants to certain “intelligent,” information processing machines, for example, computers or cellphones. Nonetheless, chemical signaling conducted through plant roots is not comparable to the waves emitted and received by cellphones. The study by scientists from the Blaustein Institute for Desert Research, which I cited in the original article, included a report on the enhanced ability of common pea plants, recipients of biochemical communication, to withstand drought, even though they did not directly experience this abiotic stress-inducer. I doubt that a cellphone would learn to function better on a low battery if it had previously received a message from another cellphone in a similar predicament.

How do these new findings bear upon dietary ethics? First, they do not mean that we should stop eating plants. Rather, the idea is not to reduce plants to storehouses of carbohydrates and vitamins or to that other source of energy so widely applauded today, biofuel. Respect for vegetal life entails nurturing all the potentialities proper to it, including those unproductive from the human point of view. It is especially pernicious to grow plants from sterile seeds, already robbed of their reproductive potential, patented and appropriated by profit-driven enterprises. Not only do these agricultural “innovations” harm farmers, who are forced to buy seeds from multinational corporations, but they also violate the capacity for reproduction at the core of the Aristotelian vegetal soul.

Given the co-evolution that brought together plants and humans, we are more interdependent with the world of vegetation, in the depths of our being, than we realize. “We are what we eat” rings even truer now that Chinese researchers discovered that molecules of rice survive the digestion process, enter the blood stream of animals and regulate the expression of mammalian genes. Violence against plants backfires, as it leads to violence against humans and against the environment as a whole, for instance when plants are genetically modified and made resistant to insects, pests or diseases. Minimally, then, respect for whatever we eat must filter through human self-respect, as the eaten becomes a part of who or what we, ourselves, are.

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Second, the ensuing dietary ethics does not imply that we should start eating more animal flesh or, for those who are neither vegans nor vegetarians, continue consuming it in good conscience. Plant stress certainly does not reach the same intensity and does not express itself the same way as animal suffering — a fact that must be reflected in our practical ethics. And yet, the commendable desire to ameliorate the condition of animals, currently treated as though they were meat-generating machines, does not justify strategic argumentation in favor of the indiscriminate consumption of plants. The same logic ultimately submits to total instrumentalization the bodies of plants, animals and humans by setting them over and against an abstract and rational mind. It follows that the struggles for the emancipation of all instrumentalized living beings should be fought on a common front.

Positively understood, the project of plant liberation would allow plants to be what they are and to realize their potentialities, often in the context of cross-kingdoms co-evolution. Inasmuch as humans and animals share the vegetal soul with plants, the potentialities of the latter are also ours, though often it is virtually impossible to recognize them as such. Since the nutritive capacity is part and parcel of vegetal life, questions regarding dietary ethics are crucial to this project. We cannot subsist on inorganic matter alone, as plants do, but we can critically question our dietary choices without prescribing a perfectly violence-free and universally applicable eating pattern. A mindful dietary pattern would combine distinct parts of the Aristotelian soul: the nutritive capacity, which forms the vegetal heritage in us, and the reasoning capacity, which Aristotle deemed to be properly human. And, when it does, plant liberation will finally be on our moral menus.

Michael Marder is Ikerbasque Research Professor of Philosophy at the University of the Basque Country, Vitoria-Gasteiz. His most recent book, “Plant-Thinking: A Philosophy of Vegetal Life” will be published by Columbia University Press this year.

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